The Lincoln–Douglas Debates of 1858 were a series of seven debates between Abraham Lincoln, the Republican candidate for the Senate in Illinois, and Senator Stephen Douglas, the Democratic Party candidate. At the time, U.S. senators were elected by state legislatures; thus Lincoln and Douglas were trying for their respective parties to win control of the Illinois legislature. The debates previewed the issues that Lincoln would face in the aftermath of his victory in the 1860 presidential election. The main issue discussed in all seven debates was slavery.
In agreeing to the debates, Lincoln and Douglas decided to hold one debate in each of the nine congressional districts in Illinois. Because both had already spoken in two—Springfield and Chicago—within a day of each other, they decided that their "joint appearances" would be held only in the remaining seven districts.
The debates were held in seven towns in the state of Illinois: Ottawa on August 21, Freeport on August 27, Jonesboro on September 15, Charleston on September 18, Galesburg on October 7, Quincy on October 13, and Alton on October 15.
The debates in Freeport, Quincy and Alton drew especially large numbers of people from neighboring states, as the issue of slavery was of monumental importance to citizens across the nation. Newspaper coverage of the debates was intense. Major papers from Chicago sent stenographers to create complete texts of each debate, which newspapers across the United States reprinted in full, with some partisan edits. Newspapers that supported Douglas edited his speeches to remove any errors made by the stenographers and to correct grammatical errors, while they left Lincoln's speeches in the rough form in which they had been transcribed. In the same way, pro-Lincoln papers edited Lincoln's speeches, but left the Douglas texts as reported.
After losing the election for Senator in Illinois, Lincoln edited the texts of all the debates and had them published in a book. The widespread coverage of the original debates and the subsequent popularity of the book led eventually to Lincoln's nomination for President of the United States by the 1860 Republican National Convention in Chicago.
The format for each debate was: one candidate spoke for 60 minutes, then the other candidate spoke for 90 minutes, and then the first candidate was allowed a 30-minute "rejoinder." The candidates alternated speaking first. As the incumbent, Douglas spoke first in four of the debates.